R&D Report 1975-36 : The filtering of luminance and chrominance signals to avoid cross-colour in a PAL colour system.
The origins of cross-colour within the PAL system are examined with the aid of one, two and three-dimensional models. Analysis shows where the luminance and chrominance energy is concentrated assuming normal scene content. Filters are then developed which restrict the luminance and chrominance energies to distinctly separate regions so minimising cross-colour. These filters range from the simplest to the most complex forms and the degradations so introduced are discussed. Elimination of cross-colour is only obtained at the expense of losing spatial or temporal resolution. The conclusion is reached that with the most complex forms of processing a resolution considerably better than that at present can be achieved with no cross-colour.